Wargrave continues the impromptu court session and shows his own proof: the letter from Lady Constance Culmington inviting him to Soldier Island. He then concludes that whoever invited them all to the island knew enough about them to create plausible reasons to invite them there. He implies that this means that the accusations of murder could be true.
Wargrave uses logic to argue that not only is Mr. Owen homicidal, everyone on this island also really is a murderer. This complicates the concept of guilt. The victims are also guilty. And it complicates any effort the victims might make to band together, because how can they trust each other?
Wargrave explains away the accusation placed against him: he was the judge for the case of Edward Seton and sentenced him to execution. Dr. Armstrong thinks to himself that he remembers the case and it seemed as if Wargrave had something personal against Seton.
Wargrave then tries to say that he is not one of the guilty parties, but it seems like although he killed someone within the law, it may have also been more personal, or he may have enjoyed it.
Vera explains that she had been a governess to Cyril Hamilton. One day Cyril swam off into the ocean while Vera wasn't paying attention and although she swam after him she couldn't catch up.
Each person has a clean way to explain away his or her accusation of guilt.
General Macarthur explains that he sent a man, Arthur Richmond, on a reconnaissance mission during the War (WWI) and he was killed. The voice had accused Macarthur of sending Richmond to his death because he had an affair with Macarthur's wife and the General says that this is completely false.
But we have already seen that that they are plagued with guilt, so their explanations cannot be completely true. In this way, Christie allows the reader to see the difference between the characters' inner lives and their presentation to the world.
Lombard explains that he got lost with some natives in Africa in the bush. He abandoned them to save himself. Anthony Marston says he ran over some children accidentally and that it wasn't his fault.
Lombard and Marston are more forthcoming about the deaths that they were involved in. This is because they do not feel as guilty about them.
Rogers explains that he and Mrs. Rogers were taking care of an old woman and when she got sick Rogers went out to find a doctor but by the time he got back she was dead. The old woman left the Rogerses money in her will.
The Rogerses are the first to demonstrate that they got something out of the death that they caused. They show a clear motive, while other characters try to present the murders they committed as accidental.
Mr. Blore explains that he was on a bank robbery case and he got the evidence that sent a man named Landor into penal servitude where he soon died. This led Mr. Blore to get a promotion.
Blore, like the Rogerses, shows that he benefited from his crime.
Mr. Armstrong says he can't quite remember the name of the patient who died during an operation. But then he thinks to himself that it really was his fault – he was drunk during the operation, but wonders who could possibly have told.
Armstrong is hiding the true story, and he, like others, believes that he can hide it because no one else should know the truth. This is contradicted by their presence on the island.
Mrs. Brent admits to nothing. She says that she has always lived by her conscience and has nothing to admit.
Mrs. Brent feels no guilt because of her sense of religious righteousness.
With each story someone in the group thinks that the speaker must be lying. After the evidence has been presented, Wargrave suggests that they should try to leave as soon as possible. Rogers tells him that there is no boat on the island and the man who delivers food, Fred Narracott, will not come again until the morning.
The characters suspect each other because most of them are lying themselves. This shows that a sense of personal guilt leads you to suspect others. Each character personally knows the depths to which a person can fall, and the lengths to which he will go to hide it—because they have all done it.
Everyone agrees that they should leave as soon as possible except Anthony Marston, who suggests that they should stay and try to solve the mystery. Then he takes a drink, chokes, and quickly dies.
Marston, the one who feels no guilt, is the first to die. As will be made evident, the killer tries to kill the victims in order of their guiltiness and guilt.